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Columbia introduced the Vinyl LP into the market in the spring of 1948. Unlike 78's which contained only a Turnover frequency in it's EQ curve, they used a different EQ curve including both a Turnover and a Rolloff frequency. After 1954, the LP industry standardized on the RCA EQ curve which became known as the RIAA EQ curve.
The RIAA curve turnover corner frequency began at 500 Hz and it's rolloff began at 2120 Hz, with the low frequency shelf occurring at 50 Hz.
The Columbia curve turnover corner frequency began lower at 300 Hz and it's rolloff began at around 1600 Hz, with the low frequency shelf occurring at 30 Hz.
Thus, early Columbia Vinyl LP's will not sound quite correct when transferred using the RIAA system. Most noticeably, they will sound too bright.
Here is a preset that you can use to produce a Columbia EQ curve. If you are using a flat preamp in conjunction with pre 1954 Columbia's, just apply this curve instead of the RIAA curve Paragraphic EQ preset that you have been acoustomed to using.
If you are using an RIAA phono preamp, first you will have to apply the Reverse RIAA curve and then re-apply this Columbia curve.
Note 1: All of these curves and presets apply to the Diamond Cut Paragraphic EQ.
Note 2: If you are using DC7 or higher, the VPA includes a Columbia LP curve which is more accurate than this one since it uses a closed form mathematical approach to the problem. Therefore, this preset is not necessary for DC7 users (or higher) who desire to decode the Columbia LP curve.
The RIAA curve turnover corner frequency began at 500 Hz and it's rolloff began at 2120 Hz, with the low frequency shelf occurring at 50 Hz.
The Columbia curve turnover corner frequency began lower at 300 Hz and it's rolloff began at around 1600 Hz, with the low frequency shelf occurring at 30 Hz.
Thus, early Columbia Vinyl LP's will not sound quite correct when transferred using the RIAA system. Most noticeably, they will sound too bright.
Here is a preset that you can use to produce a Columbia EQ curve. If you are using a flat preamp in conjunction with pre 1954 Columbia's, just apply this curve instead of the RIAA curve Paragraphic EQ preset that you have been acoustomed to using.
If you are using an RIAA phono preamp, first you will have to apply the Reverse RIAA curve and then re-apply this Columbia curve.
Note 1: All of these curves and presets apply to the Diamond Cut Paragraphic EQ.
Note 2: If you are using DC7 or higher, the VPA includes a Columbia LP curve which is more accurate than this one since it uses a closed form mathematical approach to the problem. Therefore, this preset is not necessary for DC7 users (or higher) who desire to decode the Columbia LP curve.
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